More than 500 years ago, explorers sailed to the Americas. They (bring) a few four-legged passengers along with them: pigs. Today, there are (near) six million wild pigs, also known as boars (野猪), (run) free in the US.
Boars can cause a lot of damage to crops and soccer fields. They eat baby birds and turtle eggs. Every year, they cause $1.5 billion in damage. People do all they could to stop them, boars keep going strong.
Texas is home to half of the country's boar population. Some (place) offer hunters $5 for every boar tail they bring in. High-tech means are also used (fight) against the wild pigs. The latest is a steel (钢) cage hangs off the ground— officials lay a track of tasty corn leading to cage. Special cameras record the boars approaching. Officials watch from afar. At just the right moment, the officials press a button on an app. The cage drops and traps a dozen boars all at once.
But boars are smart. They've learned ways to avoid being (catch). They know that humans hunt in daylight. Now the animals sleep during the day and eat at night, when it's much (safe). Until we find a way to outsmart them, boars will keep pigging out on farms and gardens.
